Jack-bar



J. C. KOPF.

JACK BAR.

APPLICATION FILED JUNE 14, 1919.

Patented June 1, 1920.

A TTO/MIEY 1 for its object to provide UNITED srarss PATENT OFFICE-Q JOHN G. KOPF, or BELLEVUE BOROUGH, PENNSYLVANIA, ASSIGNOR TO THE DUFF MANUFACTURING COMPANY, OF PITTSBURGH,

TION OF PENNSYLVANIA.

PENNSYLVANIA, A CORPORA JACK-BAR.

Application filed June 14,

To all whom it may concern:

Be it known that 1, JOHN G. Korr, a c1t zen of the United States, and resident of Bellevue Borough, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Jack-Bar, of which the following is a specification.

The invention relates to jacks and has a better jack-bar while reducing its cost. The strain upon these members is severe, and in order to secure proper strength in the different portions it has been common to make them of two pieces of different materials. Thus, a piece of bar steel cut with teeth has been used for the rack-bar portion; and a malleable casting for the head and toe-lift bar has been socketed over the rack-bar at the top and united therewith by a transverse rivet at the bottom passing through a spacer lug. i have proposed making the structure of a single forging, in order to simplify manufacture and for the strength which such construction. gives. This was thought impracticable, but I have found that by proper design it can be accomplished satisfactorily, and that a jack-bar thus made is not only cheaper, lighter and stronger but possesses superior mechanical advantages.

In the accompanying drawings forming a part hereof:

Figure 1 is a front elevation of a drop forged jack-bar embodying the invention;

Fig. 2 is a side elevation looking at the rack-bar portion;

Fig. 3 is a rear elevation of a fragment of the rack-bar portion;

Fig. 4 is a top plan view; and

Fig. 5 is a horizontal cross-section on the line 5-5 of Fig. 1.

The jack-bar comprises parallel vertical rack-bar and toe-lift-bar portions 1 and 2, which as is usual in this type of bar are separated by a vertical slot 3, for the purpose of accommodating a cross-element, such as a cap screw in the base (not shown). In the present construction, however, the rack bar and toe-lift bar are integral parts of a forging, which includes also a head 4: forming an integral enlargement at the top of the rack bar.

The rack-bar has a series of rack teeth 5 upon one face, for engagement by the oper- Specification of Letters Patent. Patented J 11119, 1 1920.

1919. Serial No. 304,263.

ating means of the jack. These teeth are formed to approximate dimensions in the forging operation and are afterward trimmed. At the back, opposite from the teeth, the rack-bar is deeply channeled between a pair of flanges 6 acting as runners. The rack teeth and flange channel, it will be understood, are upon the faces of the rackbar which are parallel with the common lpngitudinal plane intersecting the two ars.

The toe-lift bar 2 is formed at its outer side, that is to say upon the outside face which is transverse to said common plane, with a series of upwardly facing notched teeth 7, to coiiperate with a customary toelift. Upon the inner side this bar has a central web 8, forming the outer boundary of the slot 3, the cross-section of this bar being thus of approximate T-shape, While the rack-bar is approximately U-shaped.

A lateral extension 9 of the web 8, below' tegral connection at the bottom. These' bridge portions, of substantial depth vertically and comparatively thin through, are adapted to operate in a narrow slot in the base housing, and solidly unite the parts of the bar, in which they are assisted by the continuous formation of the flanges 11 of the head of the rack-bar portion merging over the shoulder into the flanges 12 of the toe-lift bar portion. The integral toe-lift bar portion of the present jack-bar can be made narrower in the direction perpendicular to the sides of the slot 3 than the separate toe-lift bar of the prior construction, from which it follows either that the slot can be wider, thus accommodating a stouter cross-element in the base, or that the toe-lift can'be brought in closer to the rack-bar, with consequent greater compactness and less overhang when load is upon the toe-lift. The channeled back of the rack-bar portion is of substantial advantage in reducing frictional resistance as the bar slides upon the surface of the base which is opposed to the pressure of the elevating means. When used with rough castings, without a machined bearing face to operate against, the runners 6 soon smooth the surface on the narrow bearings, and cause the efficiency of the jack to inerea' se materially With: use, the feature being one which is obtained under thenew const ruc tion o f the bar ithout additi'onal operation or expense.

What I claim as new ,is: A jack-bar consisting of a forging comprising a rack-bar portion of U cross-section and a toe-lift bar portion of T crossse ction infiegra llyijoirfed lo'y Wei) pficfbns at top and bottom, with a slot extending be- 10 tween said web portions, and an integral head afi the topof 11em 1g1o5ppgciafi eontinliing with the marginal fling of the toe-lift bar portion.

JOHN o. KOPF. 

